Description
We present a study of the nature of the blue early-type galaxies (BEGs) in the GOODS North and South fields using the GOODS archival HST ACS data. Using visual inspection, we have selected 58 BEGs and 113 normal red early-type galaxies (REGs) in the sample of 1949 galaxies with spectroscopic redshifts. We find that the BEGs are generally bluer, fainter, and less massive than the REGs, although a few BEGs are exceptionally bright and massive. The number fraction of BEGs to total early-type galaxies is almost constant (~0.3) at z<=1.1. In addition, we find that the sizes of the BEGs in a given redshift bin decrease as redshift decreases. The BEGs look similar to the REGs in the images and surface brightness profiles.
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